NEWS

Obnam NEWS
==========

This file summarizes changes between releases of Obnam.

Version 1.7.2, released 2014-03-22
--------------------------------

Bug fixes:

* Fix another bug in the FUSE plugin's file reading code, found during
  the release process of 1.7.2.

Version 1.7.1, released 2014-03-22
--------------------------------

* The `dump-repo` command now outputs JSON instead of YAML. The
  dependency on PyYAML is no longer.

Bug fixes:

* Nemo Inis found a bug in the FUSE plugin (`obnam mount`), where
  Obnam would return the wrong data when the program reading the file
  didn't read the whole file from the beginning in one read(2) system
  call.

* The test suite now skips tests that require use of extended
  attributes in the `user` namespace. This should allow the test suite
  to be run on more build servers run by various distributions.

Version 1.7, released 2014-03-15
--------------------------------

WARNING: This release has had fairly large parts of the internals
re-written. There shouldn't be any externally visible changes due to
that, but there is a chance of bugs. Be careful. Make a copy of your
backup repository before upgrading, if you can.

* The `convert5to6` subcommand has been removed. If you need to
  convert from a pre-1.0 backup repository, and haven't done so yet,
  please use Obnam version 1.6.1 or earlier to do so.

* A new `backup-finished` hook is provided by the backup plugin, so
  that other plugins may do processing at the end of a backup, such as
  report the successful backup to a monitoring system. Patch by
  Enrico Tröger.

* The FUSE plugin can now refresh its view, by having the user read
  the `.pid` file. Patch by Valery Yundin.

* New option `--always-restore-setuid` to always restore setuid/setgid
  flags in permissions, even if the restore is not being run by `root`
  or the owner of the files (as recorded in the backup).

* New option `--exclude-from` allows exclusion patterns to be given in
  a separate file (one per line), instead of in a configuration file
  or on the command line. Patch by Enrico Tröger.

* A start of a manual for Obnam. This will gain more content with
  new releases. The current versions is mainly an edited version of
  Lars's blog posts about backups, plus the Obnam tutorial from the
  Obnam homepage. See <http://code.liw.fi/obnam/manual/> for
  rendered versions (PDF, HTML).

* Most of the error messages Obnam produces now have a unique error
  code: `ERROR: R0B15DX: Cannot find requested generation for client
  havelock` for example. More error messages will gain error codes in
  future releases. The error codes are meant to be easy to search for,
  and will allow error messages to be translated in the future.

* The `obnam-benchmark` program got rewritten so that it'll do
  something useful, but at the same time, it is no longer useful as a
  general tool. It is now expected to be run from the Obnam source
  tree (a cloned git repository), and isn't installed anymore.

* The log file now includes information about the transfer overhead to
  the repository. Overhead is all the bytes that are not file content
  data: filenames, permission bits, extended attributes, etc, plus
  Obnam internal bookkeeping.

* `obnam verify` now shows progress both based on number of files and
  amount of data.

Bug fixes:

* Obnam now doesn't remove chunks that are shared between clients.
  Previously, this would sometimes happen, because only the first
  client would correctly record itself as using a chunk. Now all
  clients do that.

* Obnam now creates a `trustdb.gpg` in the temporary GNUPGHOME it uses
  during encryption operations. From version 2.0.22 (or thereabouts),
  `gpg` insists on having a `trustdb.gpg` in the GNUPGHOME it uses.

* When backing up a large file, and making a checkpoint generation in
  the middle of it, Obnam would say "continuing backup" after the
  checkpoint was finished, instead of saying the name of the file.
  This is now fixed.

Internal changes:

* The `obnamlib.Error` exception class has been replaced by the
  `obnamlib.ObnamError` class, which derives from the new
  `obnamlib.StructuredError` class. All new exceptions will need
  to be derived from `obnamlib.Error` in the future. Also, due to the
  way `StructuredError` works, it is now necessary to create a new
  exception class for each kind of error. This gives us unique the
  error codes mentioned above.

* The old `obnamlib.Repository` class is gone, and replaced with the
  `obnamlib.RepositoryInterface` class, which gets implemented for
  each repository format (there is only one, for now, but there will
  be more).

Version 1.6.1, released 2013-11-30
----------------------------------

* Fix Debian package dependencies correctly.

Version 1.6, released 2013-11-30
--------------------------------

* Stop logging paramiko exceptions that get converted into another
  type of exception by the SFTP plugin in Obnam.

* `obnam-benchmark` can now use an installed version of larch.
  Patch by Lars Kruse.

* Obnam has been ported to FreeBSD by Itamar Turner-Trauring
  of HybridCluster.

* Backup progress reporting now reports scanned file data, not just
  backed up file data. This will hopefully be less confusing to people.

* The `list-keys`, `client-keys`, and `list-toplevels` commands now
  obey a new option, `--key-details`, to show the usernames attached
  to each public key. Patch by Lars Kruse.

* New option `--ssh-command` to set the command Obnam runs
  when invoking ssh. patch by Lars Kruse.

* `obnam clients` can now be used without being an existing client.
  Patch by Itamar Turner-Trauring.

* New option `--ssh-host-keys-check` to better specify how SSH
  host keys should be checked. Patch by Itamar Turner-Trauring.

Bug fixes:

* Fix`"obnam list-toplevels` so it doesn't give an error when it's
  unable to read the per-client directory of another client, when
  encryption is used. Fix by Lars Kruse.

* Fix the encryption plugin to give a better error message when it
  looks for client directories but fails to find them. Fix by
  Lars Kruse.

* `obnam list-toplevels` got confused when the repository contained
  extra files, such as "lock" (left there by a previous, crashed Obnam
  run). It no longer does. Fix by Lars Kruse.

* The SFTP plugin now handles another error code (EACCESS) when writing
  a file and the directory it should go into not existing. Patch by
  Armin Größlinger.

* Obnam's manual page now explains about breaking long logical lines
  into multiple physical ones.

* The `/~/` path prefix in SFTP URLs works again, at least with
  sufficiently new versions of Paramiko (1.7.7.1 in Debian wheezy is
  OK). Reported by Lars Kruse.

* The Nagios plugin to report errors in a way Nagios expects.
  Patch by Martijn Grendelman.

* The Nagios plugin for Obnam now correctly handles the case
  where a backup repository for a client exists, but does not have
  a backup yet. Patch by Lars Kruse.

* `obnam ls` now handles trailing slashes in filename arguments.
  Reported by Biltong.

* When restoring a backup, Obnam will now continue past errors,
  instead of aborting with the first one. Patch by Itamar
  Turner-Trauring.

Version 1.5, released 2013-08-08
--------------------------------

Bug fixes:

* Terminal progress reporting now updated only every 0.1 seconds,
  instead of 0.01 seconds, to reduce terminal emulator CPU usage.
  Reported by Neal Becker.
* Empty exclude patterns are ignored. Previously, a configuration file
  line such as "exclude = foo, bar," (note trailing comma) would result
  in an empty pattern, which would match everything, and therefore
  nothing would be backed up. Reported by Sharon Kimble.
* A FUSE plugin to access (read-only) data from the backup repository
  has been added. Written by Valery Yundin.

Version 1.4, released 2013-03-16
--------------------------------

* The``ls` command now takes filenames as (optional) arguments, instead
  of a list of generations. Based on patch by Damien Couroussé.
* Even more detailed progress reporting during a backup.
* Add --fsck-skip-generations option to tell fsck to not check any
  generation metadata.
* The default log level is now INFO, instead of DEBUG. This is to be
  considered a quantum leap in the continuing rise of the maturity level
  of the software. (Actually, the change is there just to save some
  disk space and I/O for people who don't want to be involved in Obnam
  development and don't want to have massive log files.)
* The default sizes for the `lru-size` and `upload-queue-size` settings
  have been reduced, to reduce the memory impact of Obnam.
* `obnam restore` now reports transfer statistics at the end, similarly
  to what `obnam backup` does. Suggested by "S. B.".

Bug fixes:

* If listing extended attributes for a filesystem that does not support
  them, Obnam no longer crashes, just silently does not backup extended
  attributes. Which aren't there anyway.
* A bug in handling stat lookup errors was fixed. Reported by
  Peter Palfrader. Symptom: `AttributeError: 'exceptions.OSError'
  object has no attribute 'st_ino'` in an error message or log file.
* A bug in a restore crashing when failing to set extended attributes
  on the restored file was fixed. Reported by "S. B.".
* Made it clearer what is happening when unlocking the repository due to
  errors, and fixed it so that a failure to unlock is also an error.
  Reported by andrewsh.
* The dependency on Larch is now for 1.20121216 or newer, since that is
  needed for fsck to work.
* The manual page did not document the client name arguments to the
  `add-key` and `remove-key` subcommands. Reported by Lars Kruse.
* Restoring symlinks as root would fail. Reported and fixed by
  David Fries.
* Only set ssh user/port if explicitily requested, otherwise let ssh
  select them.  Reported by Michael Goetze, fixed by David Fries.
* Fix problem with old version of paramiko and chdir. Fixed by Nick Altmann.
* Fix problems with signed vs unsigned values for struct stat fields.
  Reported by Henning Verbeek.

Version 1.3, released 2012-12-16
--------------------------------

* When creating files in the backup repository, Obnam tries to avoid NFS
  synchronisation problems by first writing a temporary file and then
  creating a hardlink to the actual filename. This works badly on filesystems
  that do not allow hard links, such as VFAT. If creating the hardlink
  fails, Obnam now further tries to use the `open(2)` system call with
  the `O_EXCL` flag to create the target file. This should allow things
  to work with both NFS and VFAT.
* More detailed progress reporting during the backup.
* Manual page now covers the diff subcommand. Patch by Peter Valdemar Mørch.
* Speed optimisation patch for backing up files in inode numbering order,
  from Christophe Vu-Brugier.
* A setuid or setgid bit is now not restored if Obnam is not used by root
  or the same user as the owner of the restored file.
* Many new settings to control "obnam fsck", mainly to reduce the amount
  of checking being done in order to make it faster. However, fsck is
  has lost some features (checks), which will be added back in a future
  release.
* More frequent fsck progress reporting. Some speed optimisations to fsck.

Bug fixes:

* Empty values for extended attributes are now backed up correctly.
  Previously they would cause an infinite loop.
* Extended attributes without values are now ignored. This is different
  from attributes with empty values. Reported by Vladimir Elisseev.
* An empty port number in sftp URLs is now handled correctly. Found based
  on report by Anton Shevtsov.
* A bad performance bug when backing up full systems (starting from the
  filesystem root directory) has been fixed. At the beginning of each
  generation, Obnam removes any directories that are not part of the
  current backup roots. This is necessary so that if you change the
  backup roots, the old stuff doesn't hang around forever. However, when
  the backup root is the filesystem root, due to the now-fixed bug Obnam
  would first remove everything, and then back it up all over again. This
  "worked", but was quite slow. Thanks to Nix for reporting the problem.
* Obnam now runs GnuPG explicitly with the "no text mode" setting, to override
  a "text mode" setting in the user's configuration. The files Obnam encrypts
  need to be treated as binary, not text files. Reported by Robin Sheat.
* A shared B-tree concurrency bug has been fixed: If another instance of
  Obnam was modifying a shared B-tree, Obnam would crash and abort a backup,
  possibly leaving lock files lying around. Now a failure to look up a chunk
  via its checksum is ignored, and the backup continues.
* Bugs in how Python OSError exceptions were being raises have been fixed.
  Error messages should now be somewhat clearer.
* Unset or wrongly set variable "full" fixed in "obnam diff". Reported
  by ROGERIO DE CARVALHO BASTOS and patched by Peter Valdemar Mørch.
* Setuid and setgid bits are now restored correctly, when restore happens
  as root. Reported by Pavel Kokolemin.
* Obnam now complains if no backup roots have been specfied.

Version 1.2, released 2012-10-06
--------------------------------

* Added a note to `--node-size` that it only affects new B-trees.
  Thanks, Michael Brown.
* New `obnam diff` subcommand to show differences (added/removed/modified
  files) between two generations, by Peter Valdemar Mørch.
* `obnam backup` now logs the names of files that are getting backed up
  at the INFO level rather than DEBUG.
* The command synopsises for backup, restore, and verify commands now
  make it clearer that Obnam only accepts directories, not individual
  files, as arguments. (For now.)
* The output from the `show` plugin can now be redirected with the
  `--output=FILE` option. Affected subcommands: `clients`, `generations`,
  `genids`, `ls`, `diff`, `nagios-last-backup-age`.

Bug fixes:

* Notify user of errors during backups.
* The SFTP plugin now manages to deal with repository paths starting
  with `/~/` which already exist without crashing.
* Character and block device nodes are now restored correctly.
  Thanks to Martin Dummer for the bug report.
* The symmteric key for a toplevel repository directory is re-encrypted
  when a public key is added or removed to the toplevel using the
  `add-key` or `remove-key` subcommands.
* Manual page typo fix. Thanks, Steve Kemp.

Version 1.1, released 2012-06-30
--------------------------------

* Mark the `--small-files-in-btree` settings as deprecated.
* Obnam now correctly checks that `--repository` is set.
* Options in `--help` output are now grouped in random senseless ways
  rather than being in one randomly ordered group.
* Manual page clarification for `--root` and `verify`. Thanks, Saint Germain.
* Remove outdated section from manual page explaining that there is not
  format conversion. Thanks, Elrond of Samba-TNG.
* Added missing information about specifying a user in sftp URLs. Thanks,
  Joey Hess, for pointing it out.
* Manual page clarification on `--keep` from Damien Couroussé.
* Make `obnam forget` report which generations it would remove without
  `--pretend`. Thanks, Neal Becker, for the suggestion.

Version 1.0, released 2012-06-01
--------------------------------

* Fixed bug in finding duplicate files during a backup generation.
  Thanks to Saint Germain for reporting the problem.
* Changed version number to 1.0.

Version 0.30, released 2012-05-30; a RELEASE CANDIDATE
------------------------------------------------------

Only bug fixes, and only in the test suite.

* Fix test case problem when `$TMPDIR` lacks `user_xattr`. The extended
  attributes test won't succeed in that case, and it's pointless to run it.
* Fix test case problem when `$TMPDIR` lacks nanosecond timestamps for
  files. The test case now ignores such timestamps, making the test pass
  anyway. The timestamp accuracy is not important for this test.

Version 0.29, released 2012-05-27; a RELEASE CANDIDATE
------------------------------------------------------

* "obnam backup" now writes performance statistics at the end of a backup run.
  Search the log for "Backup performance statistics" (INFO level).
* "obnam verify" now continues past the first error. Thanks to Rafał Gwiazda
  for requesting this.
* Add an `obnam-viewprof` utility to translate Python profiling output
  into human readable text form.
* Bug fix: If a file's extended attributes have changed in any way, the change
  is now backed up.
* "obnam fsck" is now a bit faster.
* The shared directories in the repository are now locked only during updates,
  allowing more efficient concurrent backups between several computers.
* Obnam now gives a better error message when a backup root is not a
  directory. Thanks to Edward Allcutt for reporting the error
  (<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=654211>).
* The output format of "obnam ls" has changed. It now has one line per
  file, and includes the full pathname of the file, rather mimicking the
  output of "ls -lAR". Thanks to Edward Allcutt for the suggestion
  (<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=655095>).
* A few optimizations to sftp speed. Small files are still slow.

Version 0.28, released 2012-05-10; a BETA release
-------------------------------------------------

* `force-lock` should now remove all locks.
* Out-of-space errors in the repository now terminate the backup process.
  Previously, Obnam would continue, ignoring the failure to write. If you
  make space in the repository and restart Obnam, it will continue from
  the previous checkpoint.
* The convert5to6 black box test now works even if run by other people
  than liw.
* "obnam backup" now uses a single SFTP connection to the backup repository,
  rather than opening a new one after each checkpoint generation. Thanks to
  weinzwang for reporting the problem.
* "obnam verify" now obeys the `--quiet` option.
* "obnam backup" no longer counts chunks already in the repository in the
  uploaded amount of data.

Version 0.27, released 2012-04-30; a BETA release
-------------------------------------------------

* The repository format has again changed in an incompatible manner,
  so you will need to re-backup everything again. Alternatively, you can
  try the new `convert5to6` subcommand. See the manual page for details.
  Make sure you have a copy of the repository before converting, the
  code is new and may be buggy.
* New option `--small-files-in-btree` enables Obnam to store the contents
  of small files in the per-client B-tree. This is not the default, at
  least yet, since it's impact on real life performance is unknown, but
  it should make things go a bit faster for high latency repository
  connections.
* Some SFTP related speed optimizations.
* Data filtering is now strictly stable and priority-ordered, ensuring that
  compression always happens before encryption etc.
* Repository metadata is never filtered, so that we can be sure that
  in future if when we add backwards-compatibility we can detect the format
  without worrying about any other filtering which might occur.
* Forcing of locks is now unconditional and across the entire repository.
* Uses the larch 0.30 read-only mode to fix a bug where opening a B-tree
  rolls back changes someone else is making, even if we only use the tree
  to read stuff from.
* "obnam backup" will now exit with a non-zero exit code if there were
  any errors during a backup, and the problematic files were skipped.
  Thanks, Peter Palfrader, for reporting the bug.
* "obnam forget" is now a bit faster.
* Hash collisions for filenames are now handled.

Version 0.26, released 2012-03-26; a BETA release
-------------------------------------------------

* Clients now lock the parts of the backup repository they're using,
  while making any changes, so that multiple clients can work at the
  same time without corrupting the repository.
* Now depends on a larch 0.28, which uses journalling to avoid on-disk
  inconsistencies and corruption during crashes.
* Compression and encryption can now be used together.

Version 0.25, released 2012-02-18; a BETA release
-------------------------------------------------

* Log files are now created with permissions that allow only the owner
  to read or write them. This fixes a privacy leak.
* The `nagios-last-backup-age` subcommand is useful for setting up Nagios
  (or similar systems) to check that backups get run properly. Thanks to
  Peter Palfrader for the patch.
* Some clarification on how the forget policy works, prompted by questions
  from Peter Palfrader.
* New settings `ssh-known-hosts` (for choosing which file to check for
  known host keys), `strict-ssh-host-keys` (for disallowing unknown host
  keys), and `ssh-key` (for choosing which key file to use for SSH
  connections) allow better and safer use of ssh.
* Checkpoints will now happen even in the middle of files (but between
  chunks).
* The `--pretend` option now works for backups as well.

BUG FIXES:

* `obnam ls` now shows the correct timestamps for generations.
  Thanks, Anders Wirzenius.

Version 0.24.1, released 2011-12-24; a BETA release
-------------------------------------------------

BUG FIX:

* Fix test case for file timestamps with sub-second resolution. Not all
  filesystems have that, so the test case has been changed to accept lack
  of sub-second timestamps.

Version 0.24, released 2011-12-18; a BETA release
-------------------------------------------------

USER VISIBLE CHANGES

* The way file timestamps (modification and access times) have changed,
  to fix inaccuracies introduced by the old way. Times are now stored
  as two integers giving full seconds and nanoseconds past the full
  second, instead of the weird earlier system that was imposed by Python's
  use of floating point for the timestamps. This causes the repository
  format version to be bumped, resulting in a need to start over with an
  empty repository.
* Extended file attributes are now backed up from and restored to local
  filesystems. They are neither backed up, nor restored for live data
  accessed over SFTP.
* If the `--exclude` regular expression is wrong, Obnam now gives an
  error message and then ignores the regexp, rather than crashing.
* There is now a compression plugin, enabled with `--compress-with=gzip`.
* De-duplication mode can now be chosen by the user: the new
  `--deduplicate` setting can be one of `never` (fast, but uses more space);
  `verify` (slow, but handles hash collisions gracefully); and
  `fatalist` (fast, but lossy, if there is a hash collision). `fatalist`
  is the default mode.
* Restores now obey the `--dry-run` option. Thanks to Peter Palfreder for
  the bug report.
* New option `--verify-randomly` allows you to check only a part of the
  backup, instead of everything.
* Verify now has some progress reporting.
* Forget is now much faster.
* Forget now has progress reporting. It is not fast enough to do without,
  sorry.
* Backup now removes any checkpoint generations it created during a backup
  run, if it succeeds without errors.

BUG FIXES:

* Now works with a repository on sshfs. Thanks to Dafydd Harries for
  reporting the problem.
* Now depends on a newer version of the larch library, fixing a problem
  when the Obnam default node size changes and an existing repository
  has a different size.
* User and group names for sftp live data are no longer queried from the
  local system. Instead, they're marked as unknown.

Version 0.23, released 2011-10-02; a BETA release
-------------------------------------------------

USER VISIBLE CHANGES:

* `restore` now shows a progress bar.
* `fsck` now has more useful progress reporting, and does more checking,
  including the integrity of the contents of file content.
* `fsck` now also checks the integrity of the B-trees in the repository,
  so that it is not necessary to run `fsck-larch` manually anymore. This
  works remotely as well, whereas `fsck-larch` only worked on B-trees
  on the local filesystem.
* `force-lock` now gives a warning if the client does not exist in the
  repository.
* Subcommands for encryption now give a warning if encryption key is not
  given.
* The `--fsck-fix` option will now instruct `obnam fsck` to try to fix
  problems found. For this release, it only means fixing B-tree missing
  node problems, but more will follow.
* The default sizes have been changed for B-tree nodes (256 KiB)
  and file contents chunks (1 MiB), based on benchmarking.
* SFTP protocol use has been optimized, which should result in some
  more speed. This also highlights the need to change obnam so it can
  do uploads in the background.
* If a client does not exist in the repository, `force-lock` now gives
  a warning to the user, rather than ignoring it silently.

DEVELOPER CHANGES:

* New `--sftp-delay=100` option can be used to simulate SFTP backups over
  networks with long round trip times.
* `obnam-benchmark` can now use `--sftp-delay` and other changes to make
  it more useful.

INTERNAL CHANGES:

* Got rid of terminal status plugin. Now, the `Application` class provides
  a `ttystatus.TerminalStatus` instance instead, in the `ts` attribute.
  Other plugings are supposed to use that for progress reporting and
  messaging to the user.
* The `posix_fadvise` system call is used only if available. This should
  improve Obnam's portability a bit.

Version 0.22, released 2011-08-25; a BETA release
-------------------------------------------------

USER VISIBLE CHANGES:

* Obnam now reports its current configuration in the log file at startup.
  This will hopefully remove one round of "did you use the --foo option?"
  questions between developers and bug reporters.

BUG FIXES:

* The repository is now unlocked on exit only if it is still locked.
* A wrongly caught `GeneratorExit` is now dealt with properly.
* Keyboard interrupts are logged, so they don't show up as anonymous errors.

CHANGES RELEVANT TO DEVELOPERS ONLY:

* `setup.py` has been enhanced to work more like the old `Makefile` did:
  `clean` removes more artifacts. Instructions in `README` have been updated
  to point at `setup.py`.
* Compiler warning about `_XOPEN_SOURCE` re-definition fixed.
* Tests are now again run during a Debian package build.

Version 0.21, released 2011-08-23; a BETA release
-------------------------------------------------

USER VISIBLE CHANGES:

* Obnam will now unlock the repository if there's an error during a backup.
  For the most part, the `force-lock` operation should now be unnecessary,
  but it's still there in case it's useful some day.

BUG FIXES:

* Negative timestamps for files now work. Thanks to Jamil Djadala
  for reporting the bug.
* The documentation for --checkpoint units fixed. Thanks, user weinzwang
  from IRC.
* The connections to the repository and live data filesystem are now
  properly closed. This makes benchmark read/write statistics be correct.

Version 0.20.1, released 2011-08-11; a BETA release
-------------------------------------------------

BUG FIXES:

* More cases of Unicode strings versus plain strings in filenames
  over SFTP fixed. Thanks to Tapani Tarvainen.

Version 0.20, released 2011-08-09; a BETA release
-------------------------------------------------

BUG FIXES:

* Non-ASCII filenames over SFTP root now work. (Thanks, Tapani Tarvainen,
  for the reproducible bug report.)
* The count of files while making a backup now counts all files found,
  not just those backed up. The old behavior was confusing people.

USER VISIBLE CHANGES:

* The output of `obnam ls` now formats the columns a little prettier,
  so that wide values do not cause misalignment.
* The error message when trying to use an encrypted repository without
  encryption is now better (and suggests missing encryption being the
  reason). Thanks, chrysn.
* Obnam now supports backing up of Unix sockets.

Version 0.19, released 2011-08-03; a BETA release
-------------------------------------------------

INCOMPATIBILITY CHANGES:

* We now require version 0.21 of the `larch` library, and this requires
  bumping the repository format. This means old backup repositories can't
  be used with this version, and you need to back up everything again.
  (Please tell me when this becomes a problem.)

BUG FIXES:

* Found one more place where a file going missing during a backup may
  cause a crash.
* Typo in error message about on-disk formats fixed.
  (Thanks, Tapani Tarvainen.)
* The `--trace` option works again.
* `fcntl.F_SETFL` does not seem to work on file descriptors for files
  owned by root that are read-only to the user running obnam. Worked
  around by ignoring any problems with setting the flags.
* The funnest bug in this release: if no log file was specified with `--log`,
  the current working directory was excluded from the backup.

USER VISIBLE CHANGES:

* `obnam(1)` manual page now discusses how configuration files are used.
* The manual page describes problems using sftp to access live data.
* The documentation for `--no-act` was clarified to say it only works
  for `forget. (Thanks, Daniel Silverstone.)
* `obnam-benchmark` now has a manual page.
* The backup plugin logs files it excludes, so the user can find out what's
  going on. A confused user is an unhappy user.

INTERNAL STUFF:

* Tracing statements added to various parts of the code, to help debug
  mysterious problems.
* All exceptions are derived from `obnamlib.AppException` or
  `obnamlib.Error`, and those are derived from `cliapp.AppException`,
  so that the user gets nicer error messages than Python stack traces.
* `blackboxtests` is no longer run under fakeroot, because Debian packages
  are built under fakeroot, and fakeroot within fakeroot causes trouble.
  However, the point of running tests under fakeroot was to make sure
  certain kinds of bugs are caught, and since Debian package building runs
  the tests anyway, the test coverage is not actually diminished.
* The `Makefile` has new targets `fast-check` and `network-tests`. The
  latter runs tests over sftp to localhost.

Version 0.18, released 2011-07-20; a BETA release
-------------------------------------------------

* The repository format has again changed in an incompatible manner,
  so you will need to re-backup everything again. (If this is a problem,
  tell me, and I'll consider adding backwards compatibility before 1.0
  is released.)
* New option `--exclude-caches` allows automatic exclusion of cache
  directories that are marked as such.
* Obnam now makes files in the repository be read-only, so that they're
  that much harder to delete by mistake.
* Error message about files that can't be backed up now mentions the
  correct file.
* Bugfix: unreadable files and directories no longer cause the backup
  to fail. The problems are reported, but the backup continues.
  Thanks to Jeff Epler for reporting the bug.
* Speed improvement from Jeff Epler for excluding files from backups.
* Various other speed improvements.
* Bugfix: restoring symlinks now works even if the symlink is restored
  before its target. Also, the permissions of the symlink (rather than its
  target) are now restored correctly. Thanks to Jeff Epler for an
  exemplary bug report.
* New option `--one-file-system`, from Jeff Epler.
* New benchmarking tool `obnam-benchmark`, which is more flexible than
  the old `run-benchmark`.
* When encrypting/decrypting data with GnuPG, temporary files are no
  longer used.
* When verifying, `.../foo` and `.../foo/` now work the same way.
* New option `--symmetric-key-bits`.
* The chunk directory uses more hierarchy levels, and the way chunks
  are stored there is now user-configurable (but you'll get into trouble
  if you don't always use the same configuration). This should speed
  things up a bit once the number of chunks grows very large.
* New `--chunkids-per-group` option, for yet more knobs to tweak when
  searching for optimal performance.
* Local files are now opened using `O_NOATIME` so they can be backed
  up without affecting timestamps.
* Now uses the `cliapp` framework for writing command line applications.
  The primary user-visible effect is that the manpage now has an
  accurate list of options.
* Bugfix: Obnam now again reports VFS I/O statistics.
* Bugfix: Obnam can again back up live data that is accessed using sftp.
  Thanks to Tapani Tarvainen for reporting the problem.

Version 0.17, released 2011-05-21; a BETA release
-------------------------------------------------

* This is the second BETA release.
* The `run-benchmark` script now works with the new version of `seivot`.
  The only benchmark size is one gibibyte, for now, because Obnam's too
  slow to do big ones in reasonable time. As an aside, the benchmark
  script got rewritten in Python, so it can be made more flexible.
* Benchmarks are run using encrypted backups.
* The kernel buffer cache is dropped before each obnam run, so the
  benchmark result is more realistic (read: slower).
* Obnam now rotates its logs. See `--log-max` and `--log-keep` options
  in the manual page. The default location for the log file is now
  `~/.cache/obnam/obnam.log` for people, and
  `/var/log/obnam.log` for root.
* Obnam now restores sparse files correctly.
* There have been some speed improvements to Obnam.
* The `--repository` option now has the shorter alias `-r`, since it
  gets used so often.
* `obnam force-lock` now merely gives an error message, instead of a
  Python stack trace, if the repository does not exist.
* Obnam now does not crash if files go missing during a backup, or can't
  be read, or there are other problems with them. It will report the
  problem, but then continue as if it had never heard of the file.
* Obnam now supports FIFO files.
* Obnam now verifies checksums when it restores files.
* Obnam now stores the checksum for the whole file, not just the checksum
  for each chunk of its contents.
* Obnam's own log file is automatically excluded from backups.
* Obnam now stores and restores file timestamps to full accuracy,
  instead of truncating them to whole seconds.
* The format of the backup repository has changed in an incompatible way,
  and Obnam will now refuse to use an old repository. This means you
  will need to use an old version to restore from them, and need to
  re-backup everything. Sorry.

Version 0.16, released 2011-07-17; a BETA release
-------------------------------------------------

* This is the first BETA release. Obnam should now be feature complete
  for real use. Performance is lacking and there are many bugs remaining.
  There are no known bugs that would corrupt backed up data, or prevent
  its recovery.
* Add encryption support. See the manual page for how to use it.

Version 0.15.1, released 2011-03-21; an ALPHA release
----------------------------------------------------

* Fix `setup.py` to not import `obnamlib`, so it works when building under
  pbuilder on Debian. Meh.

Version 0.15, released 2011-03-21; an ALPHA release
----------------------------------------------------

Bugs fixed:

* Manual page GPL copyright blurb is now properly marked up as a comment.
  (Thanks, Joey Hess.)
* README now links to python-lru correctly. (Thanks, Erik Johansson.)

Improvements and other changes:

* Filenames and directories are backed up in sorted order. This should
  make it easier to know how far obnam's gotten.
* The location where backups are stored is now called the repository,
  instead of the store. Suggested by Joey Hess.
* The repository and the target directory for restored data are now
  both created by Obnam, if they don't already exist. Suggested by
  Joey Hess.
* Better control of logging, using the new `--trace` option.
* Manual page now explains making backups a little better.
* Default value for `--lru-size` reduced to 500, for great improvement
  in memory used, without, it seems, much decrease in speed.
* `obnam verify` now reports success explicitly. Based on question
  from Joey Hess.
* `obnam verify` now accepts both non-option arguments and the `--root`
  option. Suggested by Joey Hess.
* `obnam forget` now accepts "generation specifiers", not just numeric
  generation ids. This means that `obnam forget latest` works.
* I/O statistics are logged more systematically.
* `obnam force-lock` introduced, to allow breaking a lock left behind
  if obnam crashes. But it never does, of course. (Well, except if there's
  a bug, like when a file changes at the wrong moment.)
* `obnam genids` introduced, to list generation ids without any other data.
  The old command `obnam generations` still works, and lists other info
  about each generation as well, but that's sometimes bad for scripting.
* The `--dump-memory-profile` option now accepts the value `simple`, for
  reporting basic memory use. It has such a small impact that it's the
  default.
* Obnam now stores the version of the on-disk format in the repository.
  This should allow it to handle repositories created by a different
  version and act suitably (hopefully without wiping all your backups).

Version 0.14, released 2010-12-29; an ALPHA release
----------------------------------------------------

This version is capable of backing up my laptop's home directory.
It is, however, still an ALPHA release, and you should not rely on
it as your sole form of backup. It is also slow. But if you're
curious, now would be a good time to try it out a bit.

Bug fixes:

* `COPYING` now contains GPL version 3, instead of 2. The code was
  licensed under version 3 already. (Thank you Greg Grossmeier.)
* The manual page now uses `-` and `\-` correctly.
* `obnam forget` now actually removes data that is no longer used by
  any generation.
* When backing up a new generation, if any of the root directories for
  the backup got dropped by the user, they are now also removed from
  the backup generation. Old generations obviously still have them.
* Only the per-client B-tree forest should have multiple trees. Now this
  actually happens, whereas previously sometimes a very large number of
  new trees would be created in some forests. (What's good for rain
  forests is not good for saving disk space.)
* When recursing through directory trees, obnam no longer follows
  symlinks to directories.
* obnam no longer creates a missing backup store when backing up to
  a local disk. It never did this when backing up via sftp. (This
  saves me from figuring out which of `store`, `stor`, and `sorte`
  is the real directory.)

New features and stuff:

* `blackboxtest` has been rewritten to use Python's `unittest`
  framework, rather than a homegrown bad re-implementation of some of it.
* `obnam ls` interprets arguments as "genspecs" rather than generation
  identifiers. This means `obnam ls latest` works, and now `latest` is
  also the default if you don't give any spec.
* `run-benchmarks` now outputs results into a git checkout of
  <http://braawi.org/>, an ikiwiki instance hosted by
  <http://www.branchable.com/>. The script also puts the results into
  a suitable sub-directory, adds a page for the RSS feed of benchmark
  results, and updates the report page that summarizes all stored results.
* There is now a 100 GiB benchmark.
* Clients are now called clients, instead of hosts. This terminology should
  be clearer.
* The list of clients now stores a random integer identifier for each client
  (unique within the store). The identifier is used as the name of the
  per-client B-tree directory, rather than the hostname of the client.
  This should prevent a teeny tiny bit of information leakage. It also
  makes debugging things much harder.
* Various refactorings and prettifications of the code has happened.
  For example, several classes have been split off from the `store.py`
  module. This has also resulted in much better test coverage for those
  classes.
* The per-client trees (formerly GenerationStore, now ClientMetadataTree)
  have a more complicated key now: 4 parts, not 3. This makes it easier
  to keep separate data about files, and other data that needs to be
  stored per-generation, such as what the generation id is.
* `find-duplicate-chunks`, a tool for finding duplicate chunks of data
  in a files in a directory tree, was added to the tree. I have used it
  to find out if is worthwhile to do duplicate chunk removal at all.
  (It is, at least for my data.) Also, it can be used to find good
  values for chunk sizes for duplicate detection.
* The whole way in which obnam does de-duplication got re-designed and
  re-implemented. This is tricky stuff, when there is more than one client.
* `SftpFS` now uses a hack copied from bzrlib, to use openssh if it is
  available, and paramiko only if it is not. This speeds up sftp data
  transfers quite a bit. (Where bzrlib supports more than just openssh,
  we don't, since I have no way to test the other stuff. Patches welcome.)
* The way lists of chunk ids are stored for files got changed. Now we store
  several ids per list item, which is faster and also saves some space
  in the B-tree nodes. Also, it is now possible to append to the list,
  which means the caller does not need to first gather a list of all ids.
  Such a list gets quite costly when the file is quite big (e.g., in the
  terabyte size).
* New `--dump-memory-profile` option was added to help do memory profiling
  with meliae or heapy have been added. (Obnam's memory consumption finally
  got annoying enough that I did something about it.)

Removed stuff:

* The functional specification was badly outdated, and has been removed.
  I decided to stop kidding myself that I would keep it up to date.
* The store design document has been removed from the store tree.
  The online version at <http://braawi.org/obnam/ondisk/> is the
  canonical version, and is actually kept up to date.
* The benchmark specification has likewise been replaced with
  <http://braawi.org/obnam/benchmarkspec/>.


Version 0.13, released 2010-07-13; an ALPHA release
----------------------------------------------------

* Bug fix: a mistake in 0.12 caused checkpoints to happen after each
  file after the first checkpoint. Now they happen at the right intervals
  again.
* Upload speed is now displayed during backups.
* Obnam now tells the kernel that it shouldn't cache data it reads or
  writes. It is not likely that data being backed up is going to be
  needed again any time soon, so there's no point in caching it.
  (The posix_fadvise call is used for this.)
* New --lru-size option sets size of LRU cache for nodes in memory.
  The obnam default is large enough to suit large backups. This uses more
  memory, but is faster than btree's small default of 100.

Version 0.12, released 2010-07-11; an ALPHA release
----------------------------------------------------

* NOTE: This version makes incompatible changes to the way data is stored
  on-disk. Backups made with older versions are NOT supported. Sorry.
* The run-benchmark script has dropped some smaller sizes (they're too
  fast to be interesting), and adds a 10 GiB test size.
* Various speed optimizations. Most importantly, the way file metadata
  (results of lstat(2)) are encoded has changed. This is the incompatible
  change from above. It's much faster now, though.
* Preliminary support for using SFTP for the backup store added. Hasn't
  been used much yet, so might well be very buggy.


Version 0.11, released 2010-07-05; an ALPHA release
----------------------------------------------------

* Speed optimizations:
  - chunk identifiers are now sequential, except for the first one, or
    when there's a collision
  - chunks are now stored in a more sensible directory hierarchy (instead
    of one per directory, on average)
  - adding files to a directory in the backup store is now faster
  - only store a file's metadata that if it is changed
* New --exclude=regexp option to exclude files based on pathnames
* Obnam now makes checkpoints during backups. If a backup is aborted
  in the middle and then re-started, it will continue from the latest
  checkpoint rather than from the beginning of the previous backup run.
  - New option --checkpoint to set the interval between checkpoints.
    Defaults to 1 GiB.
* Options for various B-tree settings. This is mostly useful for finding
  the optimal set of defaults, but may be useful in other situations for
  some people.
  - New options --chunk-group-size, --chunk-size, --node-size,
    --upload-queue-size.
* Somewhat better progress reporting during backups.


Version 0.10, released 2010-06-29; an ALPHA release
---------------------------------------------------

* Rewritten from scratch.
* Old NEWS file entries removed (see bzr if you're interested).